<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>计时器</title>
<script type="text/javascript">
  var num=0;
  function startCount(){
    document.getElementById('count').value=num;
    num=num+1;
    setTimeout('startCount()',1000) 
  }
</script>
</head>
<body>
<form>
<input type="text" id="count" onClick="startCount()"/>
<a href="倒计时跳转页面.html">进入</a>
</form>
</body>
</html>